Current synthetic aperture radar (SAR) algorithms are implemented on platforms that are moving at a constant velocity and at a high speed, and require computationally intensive signal processing. Small platforms generally will not have constant velocity and cannot support computationally intensive signal processing. There exists a need for an algorithm which overcomes the problems associated with generating a SAR image or a GMTI image on a small unmanned aerial vehicle (UAV), robotic vehicle and/or manned vehicle. Previously, the problem encountered difficulties due to algorithm complexity, memory limitations, and DSP (computations per second) limitations. Small unmanned aerial vehicle (UAV) can provide soldiers at the platoon level with a “hover and stare” capability. Small unmanned air vehicle can be propelled using ducted fan technology and controlled using micro-electrical sensor technology. This can also provide robotic vehicles with a way of detecting and avoiding dismounts (personnel).
Aerial image radar and computer subsystems can gather and display broad and detailed information, as events occur; including position and tracking information on vehicles and personnel. The information is relayed in near-real time to ground stations via the secure links and to other ground nodes beyond line-of-sight via ultra high frequency satellite communications. The communications/datalink and operations and control subsystems comprise operator workstations displaying computer-processed data in graphic and tabular format on video screens; in order to perform surveillance, intelligence, communications and maintenance functions. Generally speaking, radar can operate in wide area surveillance, ground moving target indicator (GMTI), fixed target indicator (FTI) target classification, and synthetic aperture radar (SAR) modes, Ground moving target indicator (GMTI) is used to detect moving targets by essentially subtracting out images of stationary objects. Moving target are obtained using Doppler shift theory in GMTI modes. GMTI uses the frequency shift of the returned signal continuous surveillance from a long range. On an aircraft, the antenna can be tilted to either side in order to develop a 120 degree field of view covering hundreds of miles. The GMTI radar will detect any moving objects of sufficient size and density, such as vehicles; but will not pick up stationary objects. The system SAR mode is used produce images of stationary objects. Objects with many surface angles (for example, a the bed of a truck) will give a much better radar signature (referred to a specular returns).